The South L.A. foster mother under investigation in the fatal beating of a 2-year-old child had been the subject of five previous child-abuse complaints, it was reported today.

One complaint resulted from a substantiated allegation that she had severely neglected her own biological child in 2002, according to confidential records cited today by the Los Angeles Times.

Kiana Barker’s troubled history, which follows disclosures about her live-in boyfriend’s criminal record, has raised questions about how she could have been approved last year as a foster parent by child-welfare authorities. Under state rules, both adults should have been disqualified from caring for or living with foster children.

Barker’s home was supposed to have been a refuge for Viola Vanclief, who was born in 2007 to a schizophrenic mother who proved dangerously neglectful when off her medications, The Times reported. Instead, confidential child- welfare records reviewed by The Times show, Viola was moved from one high-risk home to another.

After Viola’s March 4 death, Barker told investigators that the toddler had been trapped in a bed frame and that she accidentally struck the child with a hammer while trying to free her, according to coroner’s records cited by The Times.

The records say Viola had multiple bruises on her body, The Times reported. The death was ruled a homicide caused by blunt-force trauma.

Barker and James Julian were arrested on suspicion of murder, then released after prosecutors sent the case back to the police and coroner for further investigation.

Los Angeles County child-welfare officials still are unable to say why Barker’s past had not ruled her out as a foster parent, The Times reported.